have you ever combined different array data with CARMA data?

[renovatio]

Dear all,

I was wondering whether any of you had an experience to combine different array data with CARMA data? For example do you know how to combine PdBI data with CARMA data? 

Many thanks in advance!

[Peter Teuben]

Most likely you will have to use UVFITS, one per windows, to get the
PdB data into miriad, and assuming all the important UV variables are
ok, use

invert vis=carma.mir,pdb.mir map=.... beam=....

as you are normally used to do. I'm assuming the PdB visibilities are
calibrated.

peter

> --
> You received this message because you are subscribed to the Google
> Groups "miriad" group.
> To unsubscribe from this group and stop receiving emails from it, send
> an email to miriad+un...@googlegroups.com.
> To post to this group, send email to mir...@googlegroups.com.
> Visit this group at http://groups.google.com/group/miriad.
> For more options, visit https://groups.google.com/groups/opt_out.

[renovatio]

Dear Peter,

Thanks a lot for the reply. 

I used FITS to convert the PdBI table into fits file, and tried read in Miriad. Miriad read it but could not find some header parameters during the 'invert'. Another way of doing this may be using Miriad task 'gildas' to convert Miriad UV table into Gildas format and then do the rest in Gildas. Thats what I am going to try next. 

cheers,

13 Ocak 2014 Pazartesi 17:15:12 UTC tarihinde teuben yazdı:

[melvyn wright]

On Thu, Jan 23, 2014 at 5:38 AM, renovatio <nebu...@gmail.com> wrote:

Dear Peter,

Thanks a lot for the reply. 

I used FITS to convert the PdBI table into fits file, and tried read in Miriad. Miriad read it but could not find some header parameters during the 'invert'.

which parameters are missing ? they can usually be put into the uvdata  using puthd or uvputhd.

Melvyn

[bka...@yorku.ca]

Hi all,

I am writing to figure out
1. How many clean components typically are used to make a map for GMCs?

2. What weighing scheme is used to reduce the effect of noise and also the effect of incomplete u-v coverage?
3. What value do you use for gain?
4. Is there any formula to estimate the image errors in GMCs or SMCs ?

best
Bahman

[melvyn wright]

On Thu, Jan 23, 2014 at 6:36 AM, <bka...@yorku.ca> wrote:

Hi all,

I am writing to figure out
1. How many clean components typically are used to make a map for GMCs?

clean deconvolves an image into point sources - not well suited for extended sources like GMCs

maximum entropy or multi resolution clean is better matched. 

2. What weighing scheme is used to reduce the effect of noise and also the effect of incomplete u-v coverage?

try natural weighting, and convolving to lower resolution using a taper in the FFT. Try several ways and compare

the results 

3. What value do you use for gain?

The default is good. 

4. Is there any formula to estimate the image errors in GMCs or SMCs ?

1. Make images using different weightings and deconvolutions and compare

the results  to estimate the errors.

 2. mosmem makes and uses a chisq image

which is a direct measure of the fit to the data in the image plane.

3. uvmodel to make uvdata from the image model and compare with the calibrated uvdata

to estimate the fit.

[renovatio]

Dear Melvyn,

The missing parameters are jperk and systemp. As you said, I can put those info to the header after figuring out that what should they be. After fixing the header problem, what else should be the same between two UV tables before combining them?

thanks!

23 Ocak 2014 Perşembe 13:43:13 UTC tarihinde melvyn wright yazdı:

[melvyn wright]

jyperk and system are a  function of observing frequency and receiver used.

The following values are given in:

http://www.iram.fr/IRAMFR/GILDAS/doc/html/pdbi-intro-html/node12.html

where

•  is the antenna efficiency (Jy K) i.e.  with  the aperture efficiency,  the antenna collecting area, and  the Boltzmann constant (22Jy.K at 85GHz, 29Jy.K at 150GHz, 35Jy.K at 230GHz and 45 Jy/K at 350GHz),
•  is the system temperature outside the atmosphere, i.e. corrected for atmospheric transmission (typically 100K SSB below 110 GHz, but 180K (170K) at 115 GHz, 150K (130K) below 150GHz, 200K (170K) above 150GHz, and 250K (200K) at 230 GHz in summer (values in brackets are for typical winter conditions)). Use  at 350GHz,

Use puthd to add jyperk and system to the IRAM uvdata

puthd in=uvdata/jyperk value=xx.x

puthd in=uvdata/systemp value=YY.Y

systemp in Miriad is an array of values for each antenna and band. If a single value does not

work, then you will need to use uvputhd with an array of values and re-write the uvdata.

Melvyn